Migrate macOS CI to GitHub Actions

[jdblischak]

This is the start of the migration from Azure to GitHub Actions. I started with the macOS CI because this is currently a bottleneck due to issues finding a suitable PyPI wheel for TileDB-Py. Thus this PR supersedes #628

Some notes:

• After the libtiledbvcf build completes, it is uploaded as an artifact, and then each API package is built in parallel using the same libtiledbvcf artifact
• Due to some runtime linking issues that I am still troubleshooting, I also added an independent job, python-standalone, that tests building libtiledbvcf and tiledbvcf-py from a single python -m pip install .. The Python test suite is run in this independent job
• The build is stuck on macos-11 because the htslib configuration step failed on both macos-12 and macos-13
• This CI workflow will only run if the pipeline itself is edited or if a file in libtiledbvcf/ or apis/ is edited. This will reduce unnecessary CI runs
• It uses Python 3.11